Repeated large-scale mass-transport deposits and consequent rapid sedimentation in the western part of the Bay of Bengal, India
Published:September 30, 2019
Yuzuru Yamamoto, Shun Chiyonobu, Toshiya Kanamatsu, Naokazu Ahagon, Kan Aoike, Nana Kamiya, Takanori Ojima, Takehiro Hirose, Takamitsu Sugihara, Saneatsu Saito, Masataka Kinoshita, Yusuke Kubo, Yasuhiro Yamada, NGHP-02 Scientists, 2019. "Repeated large-scale mass-transport deposits and consequent rapid sedimentation in the western part of the Bay of Bengal, India", Subaqueous Mass Movements and their Consequences: Assessing Geohazards, Environmental Implications and Economic Significance of Subaqueous Landslides, D.G. Lintern, D.C. Mosher, L.G. Moscardelli, P.T. Bobrowsky, C. Campbell, J. Chaytor, J. Clague, A. Georgiopoulou, P. Lajeunesse, A. Normandeau, D. Piper, M. Scherwath, C. Stacey, D. Turmel
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The National Gas Hydrate Program Expedition 02 was conducted in early 2015 using the Drilling Vessel Chikyu in the western part of the Bay of Bengal, India. During drilling off Vishakhapatnam, NE India, some bottom-simulating reflectors were penetrated, and numerous mass-transport deposits (MTDs) were identified. The recovered cores were composed of post-late Miocene muddy slope deposits containing the late Miocene–Pliocene hiatus that is widespread in that region. Based on detailed visual core descriptions and calcareous nannofossil biostratigraphy, two major MTD-rich intervals were identified: the Pleistocene interval above the hiatus, and the middle–late Miocene interval below it. Although the MTDs in both intervals are composed of variously coloured clay–silt blocks in an olive-black or olive-grey silty clay matrix (muddy MTDs), the Pleistocene MTDs consist of larger-sized blocks (mostly less than a few metres but with some >10 m) without clear shear fabrics, whereas the Miocene MTDs contain smaller blocks (<0.1 m) with asymmetrical shear fabrics. The muddy blocks are composed of older components (Pliocene–Cretaceous) compared with the depositional ages of the MTDs. The high abundance of MTDs above the hiatus and the depositional ages of the interbedded coherent layers indicate that large-scale MTDs occurred repeatedly during the Pleistocene. Such repeated MTDs contributed to maintaining the high sedimentation rate in this area and potentially provided stable pressure and temperature conditions for the formation of gas hydrates.
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Subaqueous Mass Movements and their Consequences: Assessing Geohazards, Environmental Implications and Economic Significance of Subaqueous Landslides
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The challenges facing submarine mass movement researchers and engineers are plentiful and exciting. This book follows several high-profile submarine landslide disasters that have reached the world's attention over the past few years. For decades, researchers have been mapping the world's mass movements. Their significant impacts on the Earth by distributing sediment on phenomenal scales is undeniable. Their importance in the origins of buried resources has long been understood. Their hazard potential ranges from damaging to apocalyptic, frequently damaging local infrastructure and sometimes devastating whole coastlines. Moving beyond mapping advances, the subaqueous mass movement scientists and practitioners are now also focussed on assessing the consequences of mass movements, and the measurement and modelling of events, hazard analysis and mitigation. Many state-of-the-art examples are provided in this book, which is produced under the auspices of the United Nations Educational, Scientific and Cultural Organisation Program S4SLIDE (Significance of Modern and Ancient Submarine Slope LandSLIDEs).